Aes encryption how does it work

The mentioned steps are to be followed for every block sequentially. Upon successfully encrypting the individual blocks, it joins them together to form the final ciphertext. The steps are as follows:. Now that you understand the basic steps needed to go through the encryption procedure, understand this example to follow along. As you can see in the image above, the plaintext and encryption convert keys to hex format before the operations begin. Accordingly, you can generate the keys for the next ten rounds, as you can see below.

You need to follow the same steps explained above, sequentially extracting the state array and passing it off as input to the next round. This state array is now the final ciphertext for this particular round. This becomes the input for the next round. Depending on the key length, you repeat the above steps until you complete round 10, after which you receive the final ciphertext. In May of , AES was approved to become the US federal standard and quickly became the standard encryption algorithm for the rest of the world as well.

With any kind of encryption, there are always trade-offs. You could easily have a standard that was exponentially more secure than AES, but it would take too long to encrypt and decrypt to be of any practical use. In the end, the Rijndael block cipher was chosen by NIST for its all-around abilities , including its performance on both hardware and software, ease of implementation and its level of security. Be aware that the following example is a simplification, but it gives you a general idea of how AES works.

Under this method of encryption, the first thing that happens is that your plaintext which is the information that you want to be encrypted is separated into blocks. Key expansion involves taking the initial key and using it to come up with a series of other keys for each round of the encryption process.

Although they look like random characters and the above example is just made up each of these keys is derived from a structured process when AES encryption is actually applied.

In this step, because it is the first round, our initial key is added to the block of our message:. This is done with an XOR cipher , which is an additive encryption algorithm. The characters are just a stand-in to try and make things easier to understand. In this step, each byte is substituted according to a predetermined table. This is kind of like the example from the start of the article, where the sentence was coded by changing each letter to the one that comes after it in the alphabet hello becomes ifmmp.

Instead, there is an established table that can be looked up by the algorithm, which says, for example, that h3 becomes jb , s8 becomes 9f , dj becomes 62 and so on. Shift rows is a straightforward name, and this step is essentially what you would expect.

The second row is moved one space to the left, the third row is moved two spaces to the left, and the fourth row is moved three spaces to the left. This gives us:. This step is a little tricky to explain. Well, this is where we start to use them. We take the result of our mixed columns and add the first round key that we derived:. After the last round key was added, it goes back to the byte substitution stage, where each value is changed according to a predetermined table.

Then it goes through the mix columns equation again. After that, another round key is added. At the start, it was mentioned that AES has key sizes of either , or bits.

When a bit key is used, there are nine of these rounds. When a bit key is used, there are So the data goes through the byte substitution, shift rows, mix columns and round key steps up to thirteen times each, being altered at every stage.

After these nine, 11 or 13 rounds, there is one additional round in which the data is only processed by the byte substitution, shift rows and add round key steps, but not the mix columns step. The mix columns step is taken out because at this stage, it would just be eating up processing power without altering the data, which would make the encryption method less efficient. It seems like a completely random string of characters, but as you can see from these examples, it is actually the result of many different mathematical operations being applied to it again and again.

This means the data is divided into a four-by-four array containing 16 bytes. Each byte contains eight bits. Hence, 16 bytes multiplied by 8 bits is yields a total of bits in each block.

Regardless of this division, the size of the encrypted data remains the same. In other words, bits of plaintext yields bits of ciphertext.

We'll get more into how these round keys are generated later. Suffice to say that, multiple rounds of modification generate a new round key every time. With each passing round, the data becomes more and more secure and it becomes harder to break the encryption. Because these encryption rounds make AES impenetrable! There are just way too many rounds that hackers need to break through to decrypt it. Put it this way: A supercomputer would take more years than the presumed age of the universe to crack an AES code.

While the key length of this encryption method varies, its block size — bits or 16 bytes — remains the same. Let's take an app for example. The practical effect is it will require more raw power from your battery, so your phone will die faster. So while using AES bit encryption is the gold standard , it's just not feasible for everyday use.

AES is one of the most trusted systems in the world. It's been widely adopted in multiple industries that need extremely high levels of security.

If you rely on password managers to remember your login credentials for your multiple accounts, likely, you've already encountered AES! Those messaging apps that you use, like WhatsApp and Facebook Messenger? Yeah, they use this, too. And of course, let's not forget the apps your bank created to let you manage your finances online. After you find out how AES encryption works, you'll breathe much easier with the knowledge that your information is in safe hands!

However, by the s, DES was no longer secure enough because it could be broken in only 22 hours. So, the government announced a public competition to find a new system that lasted over 5 years. The benefit of this open process was that each of the submitted encryption algorithms could be subjected to public security.

Moreover, because multiple minds and eyes were involved, the government maximized its chances of identifying and fixing flaws. Rijndael was named after the two Belgian cryptographers who created it, Vincent Rijmen and Joan Daemen. In , it was renamed the Advanced Encryption Standard and published by the U. Its open nature means the AES software can be used for both public and private, commercial and noncommercial applications. So far, we know that these encryption algorithms scramble the information it's protecting and turn it into a random mess.

I mean, the basic principle of all encryption is each unit of data will be replaced by a different one, depending on the security key.

But what exactly makes AES encryption secure enough to be considered the industry standard? The AES encryption algorithm goes through multiple rounds of encryption. It can even go through 9, 11, or 13 rounds of this. After the last round, the algorithm will go through one additional round. In this set, the algorithm will do steps 1 to 7 except step 6. It alters the 6th step because it would not do much at this point.

Remember it's already gone through this process multiple times. So, a repeat of step 6 would be redundant. The amount of processing power it would take to mix the columns again just isn't worth it as it will no longer significantly alter the data. A r andom set of jumbled characters that won't make sense to anyone who doesn't have the AES key.

Some ciphers may be included in certain selections but absent in others. Not AES. AES will almost always be present in all but a few. Why is this so? It all started when the US government began looking for a new encryption algorithm that could be used to protect sensitive data. Unfortunately, that cipher was later proven to be insecure, prompting the government to look for a replacement.

The selection process was very stringent, taking five years to complete. During that span, many experts from the cryptographic community carried out detailed tests and painstaking discussions to find vulnerabilities and weaknesses.

The participation of different sectors, which showed the openness of the selection process, speaks volumes of how credible the process was. Although the cipher's strength against various attacks was a major consideration in choosing the standard, it included other factors like speed, versatility, and computational requirements.

The government wanted an encryption standard that wasn't just strong, but also fast, reliable and easily implemented in both software and hardware — even those with limited CPU and memory.